Burner for furnaces



April 11, 1939. H. B. BARBER BURNER FOR FURNACES original Filed July sl, 1937 y lm ////////a m m l I Vlrl llfllrlwllvll l md WJ mmv@ Tuuuununuuuundwwmwl H5. Barber l /nv E \N (Ittorneg Il s ai li -IIIH I IM@ QN M Patented Apr. 11, 1939 4UNITED STATES PATENT OFFICE 2,153,951 BURNER Fon FURNAoEs\ Application July 31, 1937, Serial No. 156,677 Renewed November 25, 1938 8 Claims.

Heretofore in the firing of forge furnaces, the tory material I4 within a metal casing I5, havfuel most generally used has been fuel oil pri/ marily because the high degree of luminosity from an oil ame gives an exceptionally high heating rate and because the scale produced on the work, such as steel, is of a type that is not particularly detrimental to forming equipment. Scale-free work' is, of course, preferred from an economic standpoint but a soft loose scale, such as is produced by an oil flame, will be tolerated, whereas a hard tight scale, such as is produced by flame from a preformed explosive mixture of air and fuel gas, will not be tolerated because a hard tight scale causes excessive wear on the forming tools.

The object of the present invention is to pro-v vide a method of and an apparatus' for utilizing fuel gas, and more particularly natural gas, for firing a forge furnace with results comparable to those obtained by utilizing fuel oil.

In accordance with the present invention some of the fuel gas, before being introduced into the forge furnace, is cracked in a heated chamber whereinto gases of combustion from a premix burner are discharged. Some air is also introduced into said chamber to insure partial combustion of the fuel gas. The balance of the fuel gas required to heat the furnace is caused to flow through said chamber. For a more complete understanding of the invention reference is made to the detail description taken in connection with the accompanying drawing wherein the preferred form of apparatus for the practice of the invention is shown.

In the drawing,

Fig. l is a side elevation of a conventional forge furnace with the improved ring apparatus at one end thereto;

Fig. 2 is a longitudinal vertical cross section, on a larger scale than Fig. 1, of the improved firing apparatus;

Fig. 3 is a Vertical cross section of said apparatus, and

Figs. 4 and 5 show different forms of burners that may be used with the firing apparatus.

lll indicates-a conventional forge furnace having a horizontally extending heating or firing chamber Ill' in a side Wall of which is a longitudinally extending slot II for the insertion and removal of the work to be forged. The improved firing apparatus is generally indicated at B and comprises a cylindrical chamber I2 which at one end is in open communication with the furnace chamber IIl' by way of a cylindrical throat I3. The walls of the chamber I2 are made of refracing a radial ange I6 by means of which the casing is secured to the end wall of the furnace.

I1 indicates a pressure premix burner which fires into the chamber I2 tangentially thereof at a point near its end wall I8. The gases of combustion from this burner heat the Walls of the chamber to incandescence and follow the periphery of the chamber in circular fashion on their way to the throat I3 leading to the furnace chamber. l,

I9 indicates a pressure fue'lx gas supply pipe ,which discharges into the chamber I2 through a tangential port 20 arranged in the same circular direction as the burner I l. Said port is located in relatively close proximity to the chamber end Wall I8 and is circumferentially spaced from the burner I'l. The fuel gas thus discharged from the port 20 follows the periphery of the chamber in circular fashion along with the gases of combustion from the burner I'l and due to the high temperature prevailing in the chamber is cracked with resultant production of free carbon in suspension. The amount of fuel gas thus discharged into the chamber I2 is substantially less than what is required to produce the necessary heat in the forge furnace.

2l indicates a pressure air supply pipe which discharges into the chamber I2 through a tangential port 22 arranged in the same circular direction as the gas port 20. 'Ihe preferred position of port 22 is as shown in Fig. 2, that is to say, it is more remote from said throat i3 than it is from the end wall I8 of lthe chamber I2, thus insuring that partial combustion of the fuel gas will take place.

The amount of air admitted to the chamber I2 through port 22 is only a small fraction of what is required to support complete combustion of the gas andthe purpose of the air thus admitted to the chamber is to support partial combustion of the gas and thus assist in the cracking thereof. Cracking of the gas requires time as well as temperature. 'I'he temperature is provided by the premix burner and the time factor is taken care of by causing all of the gas to follow the periphery of the chamber while flowing toward the furnace chamber.

The additional fuel required for heating the forge furnace may be supplied either by a nonpremix or by a premix burner arranged to fire axially through the reaction chamber I2. A nonpremix burner is shown in Fig. 2, the same comprising two concentric tubes 23 and 24 with an annular space 25 between them, the center tube being connected to a gas supply pipe 26 and the outer tube to an air supply pipe 21. Instead of being inside of the air tube, the gas tube may surround the air tube as shown in Fig. 4, the gas tube being indicated at 24' and the air tube at 23 and the gas and air supply pipes at 26 and 21 respectively. In a non-premix burner of the kind disclosed, the air and gas are flowed therefrom with about the same velocity which need only be sufficient to insure that the composite stream shall flow straightforwardly through the chamber I2. A premix burner is indicated in Fig. 5, the same comprising a single tube 28 to which premixed air and gas is supplied by any preferred mixing apparatus not shown. When a premix burner is employed the mixture will have to issue from the burner with sufficiently high velocity to carry it well into the throat I3 of the furnace before the mixture begins to burn. Since the other gases admitted to the chamber l2 flow therein in a circular direction, there will be very little mixing of the gases from the burner which fires axially into the chamber I2 from its end wall I8 until the various gases flow through the throat I3. Moreover, since some of the gases admitted to the chamber I2 are gases of combustion from the premix burner II, the fuel gases from the axially flring burner will become diluted with such gases of combustion in passing through the throat I3 with the result that combustin will not be localized at the throat end of firing chamber I0'. It should be noted that the direction of the rotation of the gases in the chamber I2 is such that the gases on entering the firing chamber Ill' now in a direction downwardly along the back Wall of the ring chamber and across the -hearth toward the work slot Il and thereby sweep air tending to enter by way of the work Slot II away from the work.

By firing the furnace I0 in the manner described, the result obtained as regards the con dition of the work is substantially the same as that obtained when the furnace is fired by fuel oil. If at times it should be desired to fire the furnace with oil instead of gas, this may be readi ly accomplished by removing the axially ring burner at the end of the reaction chamber and substituting an ordinary atomizing oil burner.

What I claim is:

l. Apparatus for firing a heating chamber ccmprising, in combination, a tubular body which at one end communicates with said chamber and which at its other end is closed by a Wall having an ope ng centrally of said body, a burner positioned said opening for firing into said chamber through said body, a premix burner positioned to discharge tangentially into said body, and means for discharging a stream of fuel gas into said body in the same circular direction as the flow of gases from the said premix burner.

2. In the combination specified in claim 1, the burner which is positioned in said opening having parallelly extending discharge passages for air and fuel gas respectively.

3. Apparatus for firing a heating chamber comprising, in combination, a tubular body which at one end communicates with said chamber and which at its other end is closed by a wall having an opening centrally of said body, a burner po sitioned in said opening for firing into said chamber through said body, a premix burner positioned to discharge tangentially into said body, and means for discharging separate streams of air and fuel gas into said body in the same circular direction as the now of gases from the said premix burner, the amount of air in said air stream being substantially less than is required to cause complete combustion of said fuel gas.

4. Heat producing apparatus comprising in combination a refractory body forming a cylindrical reaction chamber closed at one end and open at its other end and having at least two tangentially extending inlet ports arranged to discharge into the chamber in the same circular direction, said ports being in communication with pressure air and pressure fuel gas, respectively, a pressure premix burner positioned to discharge tangentially into said chamber in the same circular direction as said ports, and means for introducing fuel gas and air under pressure axially into said chamber from its closed end.

5. In apparatus for firing a furnace, the combination of a body forming a circular chamber which is closed at one end and which at its other end is in open communication with said furnace, said body having at least three ports leading tangentially into said chamber in the same circular direction, a means for introducing air under pressure into said chamber through one of said ports, means for introducinga hydrocarbon gas under pressure into said chamber through the second of said ports, means for introducing a mixture of air and fuel under pressure into said chamber through the third of said ports, and means for controlling the relative amounts of air and hydrocarbon gas admitted to said chamber whereby .to effect cracking of the hydrocarbon gas.

6. In the combination specied in claim 5, the second port being closer the closed end of said chamber than the air port.

7. In the combination specified in claim 5, the third port being adjacent the closed end of said chamber and the second port being closer to said closed end than the air port.

8. In combination, a furnace, and means for nring the furnace comprising a circular refractory chamber, one end of which opens into the furnace and the other end of which is closed, a premix burner discharging tangentially into said chamber, means for discharging a stream of fuel gas into said chamber in the same circular direction as the flow of gases from the premix burner and means for discharging a constituent of combustion centrally into the chamber from the closed end thereof.

HUGH B. BARBER. 

